1. Technical Field
The disclosure relates to power supply circuits, and particularly to a current balance circuit.
2. Description of Related Art
In high-powered power supply systems, a plurality of power supplies are connected in parallel or a power supply is divided into a plurality of current branches connected in parallel to provide high current to at least one load, which both need to balance currents. In a power supply system with the plurality of power supplies, a pulse width modulation (PWM) controller is utilized to adjust output voltage to the at least one load according to current feedback signals, to balance the currents. If the current feedback signals are obtained via resistors, the current feedback signals are easy to be influenced by common mode noises. If the current feedback signals are obtained via current Hall elements, the power supply systems have a high cost and occupy large space.
In a power supply system with a power supply divided into the plurality of current branches, impedance among the plurality of current branches often do not match. Although copper foil impedance can be used to balance currents through the plurality of current branches, the copper foil impedance is easy to be influenced by temperature and current density, which influences veracity of current balance.